Commitments and Contingencies - Estimated Amounts of Regular, Discharge Payments Expected to Pay and Estimated Recoveries from Charged-off Loans (Parenthetical) (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Total Payments	$ 107,081
CUSO [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Amount of offset to repay	9,500
Recoveries from charged-off loans	1,049
Sixth Amendment [Member] | CUSO RSA [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Total Payments	$ 8,905